Regensburg 2016 – scientific programme
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MA: Fachverband Magnetismus
MA 17: Poster Session I
MA 17.90: Poster
Tuesday, March 8, 2016, 09:30–12:30, Poster B1
Twofold and fourfold symmetric anisotropic magnetoresistance effect in a model with crystal field — •Satoshi Kokado1 and Masakiyo Tsunoda2 — 1Shizuoka University, Hamamatsu, Japan — 2Tohoku University, Sendai, Japan
We theoretically study
the twofold and fourfold symmetric anisotropic magnetoresistance
(AMR) effect [1].
We first extend
our previous model [2,3] to a model
including the crystal field effect [1].
Using the model, we next obtain an analytical expression of the AMR ratio,
i.e.,
AMR(φ)=C0 + C2 cos(2 φ) + C4 cos(4 φ),
with C0=C2 − C4 [1].
Here,
φ is the relative angle
between the magnetization direction and the electric current direction
and
C2 (C4) is a coefficient of the twofold (fourfold) symmetric term.
The coefficients C2 and C4 are expressed
by a spin-orbit coupling constant, an exchange field,
a crystal field, and s-s and s-d scattering resistivities.
Using this expression,
we analyze the experimental results for Fe4N [4,5],
in which |C2| and |C4| increase with decreasing temperature.
The experimental results can be reproduced
by assuming that
the tetragonal distortion increases with decreasing temperature.
[1] S. Kokado et al., J. Phys. Soc. Jpn. 84, 094710 (2015).
[2] S. Kokado et al., J. Phys. Soc. Jpn. 81, 024705 (2012).
[3] S. Kokado et al., Adv. Mater. Res. 750-752, 978 (2013).
[4] M. Tsunoda et al., Appl. Phys. Express 3, 113003 (2010).
[5] K. Kabara et al., Appl. Phys. Express 7, 063003 (2014).